Engine starter drive



May 6, 1947. D. MILLER ENGINE STARTER DRIVE Filed April 5, 1945 2 Sheets-Sheet l MIC".

WITNESS 2m y 1 D. MILLER 2,420,288

ENGINE STARTER DRIVE Filed April 5, 1945 2 Sheets-Sheet 2 INVEN TOR.

WITNESS pmaldfifihller AT ORNEY Patented May 6, 1947 UNITED STATES PA'I'EN'I OFF-ICE- ENGINE STARTER DRIVE Donald L. Miller, Pine City, N. Y., assigno'r to Bendix Aviation Corporation, South Bend, Incl, a corporation of Delaware Application April 5, 1945', 'Serial No. 586,675

'Ciaims.

The present invention relates to an engine starter drive and "more particularly to that type of starter drive in which a block of elastic inate rial is used for transmitting the cranln'ng torque of a starting 'motor to the engine to be started.

It is an object of the invention to provide a novel starter of the above type which is-sl-ior-t and coihpact-andcomriosedoi very few parts in order to facilitate assembling and servicing of the drive.

It is another object of the invention to provide such a device in which the block of elastic material transmits by torsion substantially all of the cranking load.

It is a further object to provide such a device utilizing the elastic block as a spacing and posttioning member for other parts of the drive.

It is a further object of such a-device to provide a form of elastic block which acts as a cover for the traversing elements of the drive so as tc exclude foreign matter such as mud and oil.

-It is a further object to provide such a drive including novel interlocking and securing arrangements for the parts.

It is a further object to provide such a device incl-uding an anchor pin-and an'anti-dr'iit spring having a seating disc in which the seating disc acts "as an en'dwis'e lock for the anchor pin.

Further objects and advantages will be apparent from the following description taken in connection withacoompanying drawing, in which:

Fig. 1 is a side elevation, partly in section, of a preferred embodiment of the invention, the parts being shown in idle position;

Fig. -2 is a View similar to Fig. 1, showing the parts of the drive in operating position;

Fig. 3 is a representation in perspective of the control member and the ring for demountably attaching the control memberto the elastic block;

Fig. 4 is a side elevation partly in section of a second embodiment of the invention;

Fig. 5 is a view similar to Fig. 4 showing the starting drive in operating position; and

Fig, 6 is a perspective view of certain details of the starting drive shown disassembled.

Referring first to Fig. 1 in the drawing, the

starting drive is mounted on a motor shaft I which maybe an extended armature shaft of an electric motor 2, the shaft being journalled in an outboard bearing 3 on the motor housing. An

operating member in the form of a hollow shaft 4, threaded for a portion of its length as indicated at 5, is fixed to the motor shaft as by means of an anchor pin 6 traversing the shafts. The endofthe screw shafti is enlarged in diame limited by a shoulder 21 on the screw shaft.

2 ter providing an abutment shoulder adjacent to the axis of the anchor pin. A pinion member 8, provided with a disc-like flange 9 fixed thereon in any suitable manner, is 'slidably journalled on the motor shaft ji imposition to be traversed into and out of engagement with a ineinb'er er the engine tone startedsuchasa ring gear I l. Means for traversing and rotating the pinion are provided comprising a control nut inez'nb'er l2 threaded on the hollow shaft 4 and having a flange cr rib 1'3 on the rear portion thereof provided with radially extenuing-'dnvin :1u s ii. A ring member 1'5 is r noiih'tedon'the nut l2 and is provided with radial slots l6 adapted to receive the iug's M, with an internal annular groove H for reception of a snap ring 8 serving to 'detachalolv lock the ring member in the slot 12. Yieldable spacing and torque transmitting means are provided between the ring I5 and pinion flange 9 in the form "of an elastic hollow shaft or sleeve l9 of material such as rubber, fixedly anchored at its ends to said ring and pinion flange by suitable means such as by bonding or cementing, and "enclosing the space between the nut and pinion.

Means for opposing drifting of the pinion 8 into contact withengine gear l I while the starter drive is idle are provided including a spring 2| seated at one end on the control member and at the other end on a flanged disc 22. Disc 22 is mounted on the hollow shaft 4 within the elastic sleeve [9 in position to bear against shoulder 1 where it overlies the exposed ends of the anchor pin -'6 so as to provide an effective looking riie'ainsio 'r the pin. A'smooth portion 23 of reduced diameter-is provided adjacent to threads 5 onthe screw shaft '6 and a counter-bore 2 4 is formed in *the control nut 12 so that the nut can run (iii the ends of the threads '5 of the shaft.

in order to insure immediate re-eng'agernent of the threads "at the moment when energy is apthe threads'5. The travel of the thirnble 25, and

consequently the expansion of "the spring '25 is A collar 28, formed somewhat as an enclosiire for the spring provides *a seat for theoiipo'site end of "the spring, and a lock snap ring 29' is used 3 back of the collar 28 to maintain spring 25 under initial compression.

In operation of the device, rotation of the motor shaft l in the direction of the arrow (a) causes the screw shaft 4 to traverse the nut member l2 to the right in Fig. 1 until its movement is stopped by engagement with disc 22 which is seated against the shoulder i. Pinion 8 is consequently traversed into mesh with engine gear II by virtue of the elastic connection is between the control nut l2 and the pinion 8. At the moment when the screw shaft 4 starts to rotate, the pressure of the spring 25 insures initial engagement of the nut with the threads 5 of the screw shaft. As soon as the traversal of the control nut I2 is stopped by the shoulder l, torque is applied to the pinion 8 through the driving connection to crank the engine. If abutment of the teeth on pinion 8 and engine gear H should occur during the meshing movement thereof, the endwise pressure on the resilient sleeve It! would cause axial yield thereof thus building up endwise and rotary pressure on the tooth ends to rotate the abuttin pinion tooth and cause it to enter the next tooth space of the ring gear.

In the embodiment of the invention shown in Figs. 4, 5 and 6, a starter of the inboard-meshing type is provided. Referring to Fig. 4 of the drawings, a power shaft 3i which may be the extended armature shaft of a motor 32 extends outwardly to receive a screw shaft 33 on its free end. The screw shaft 33 is threaded at 34 for a portion of its length and enlarged in diameter at the inner end to form a houlder 35. Suitable means such as a pin 36 traversing the enlarged portion of the screw shaft and the power shaft is provided for anchoring the screw shaft on the power shaft.

A pinion 31 having a flange 38 fixed thereon in any suitable manner is slidably journalled on the power shaft 3| in position to be traversed into mesh with the engine gear 39. Control means for actuating the pinion 3'! is provided in the form of a flanged or ribbed nut member 4!] journalled on the smooth portion 4| of the screw shaft 33 and counterbored at 42 for a portion of its length. Flexible means are provided for connecting and spacing the nut member 40 with respect to the pinion 31 in the form of a unit comprising an elastic hollow shaft or sleeve 43 fixed at its ends in any suitable manner as by bonding to similar rings 44 and 44',

Detachable means for uniting said rings to the adjacent pinion member 31 and control member 40 are provided in the form of keyed connections in which radial slots 45 and 46 in the lateral faces of the rings 44 and 44' are interfitted with radial lugs 41 and 48 projecting radially from the flanges of the pinion member and control member respectively to form a driving connection therebetween. Locking snap rings 49 and 55 are held Within annular recesses 5| and 52 formed in rings 44 and 44' adjacent the pinion and control member flanges respectively to hold the lugs within their mating slots.

Means are provided for performing the combined functions of opposing drifting of the pinion 31 from disengaged position and locking the anchor pin 36, in the form of a cupped disc or thimble 53 located by the radial shoulder 35 on the screw shaft 33. The thimble 53 is so located as to overlie the anchor pin hole in the screw shaft 33 and also forms a seat for one end of an anti-drift spring 54, the other end of which is seated on the control member 45. Arrangement 4 is made for permitting the threads of control nut to run off the threads of the screw shaft 33 by counterboring the control nut as stated, and .by terminating the threads of the screw shaft 33 so as to provide shoulders 55 and 56 respectively. In order to assure immediate re-engagement of the threads at the moment power is applied to the shaft 3|, means are provided in the form of an expansion spring 5'! bearing through a supporting thimble 58 against the control member 40 for applying pressure between the thread shoulders 55 and 56. The outer end of the spring 51 is seated upon a cup-shaped collar 59 to enclose the spring when in idle position and is held in assembled relation with the screw shaft by a locking snap ring Bl held in a groove in the smooth reduced diameter 62 of the screw shaft 33.

When assembling the starter drive on the starting motor shaft 3|, the pinion member 31 and locking ring 49 are slid over the shaft followed by the screw shaft 33 which is held in place by inserting the anchor pin 36. The locking thimble 53 is then pressed against the shoulder 35 and the anti-drift spring 54 placed upon the thimble. The elastic sleeve 43 and its attached rings 44 and 44 are placed over the spring 54 as a unitary sub-assembly and the lugs 41 are locked into slots by snap ring 49. The control nut 40 is next slipped over screw shaft 33 and simultaneously its protruding lugs 48 are assembled in the slots 46 and are locked therein by the snap ring Lastly the thread remeshing device is assembled by slipping the thimble 53 over the smooth surface 82, seating the spring 51 on thimble 58, seating the outer end of the spring 51 in collar 59 and pressing it along the surface 62 until the lock ring 6| can be set into place.

The operation of this embodiment of the invention is substantially similar to that previously described except that the pinion moves toward the motor when it enters into mesh with the engine gear, whereby the pinion is closely adjacent the motor bearing during the cranking operation, thus rendering an outboard bearing for the motor shaft unnecessary.

It will be seen that there is here provided a novel construction in which a rubber sleeve or shaft rovides the torque connection for driving the pinion and constitutes a sheltering casing for substantially enclosing the inner parts of the starting drive when in idle position, and spacing means for the pinion with respect to other parts of the drive.

Furthermore, it will be seen that there is here provided a novel locking mechanism for the screw shaft anchor pin in combination with anti-drift means for the pinion.

It will be understood that the forms of starter drive disclosed are not exclusive and changes may be made in the form and arrangement of the parts without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

1. In an engine starter, a motor shaft, a pinion mounted thereon for traversal into engagement with a member of an engine to be started and a flange on said pinion, an operating member fixed to the motor shaft and a flanged control member concentric with said operating member, means including an inclined connection between said operating and control members for traversing said pinion, means on the operating member for arresting the movement of the control member, and a sleeve of elastic material fixed at its ends to the pinion and control member flanges constituting the sole operative connection to the pinion. I

2. In an engine starter, a motor shaft, a pinion member mounted on said shaft for traversal into and out of engagement with a member of an engine to be started, a screw shaft mounted on the motor shaft and means anchoring said screw shaft thereon, means opposing drifting of the pinion from idle position including a disc, said disc also serving to lock said anchoring means on the screw shaft, and means actuating the pinion member including a control member threaded on the screw shaft, and a cylindrical block of elastic material attached at its ends to said control member and pinion member.

3. In an engine starter, a motor shaft, a pinion slidably mounted thereon for axial movement into and out of engagement with a member of an engine to be started, a screw shaft on the motor shaft, a control member threaded thereon for actuating the pinion, means including a spacing and power transmitting member of elastically deformable material substantially enclosing the starter in idle position and yieldingly connecting said control member and pinion for rotary and longitudinal movement in unison, means for opposing drifting of the pinion from inoperative position including a spring and a disc forming a seat for one end thereof, and means for anchoring the screw shaft on the motor shaft, said anchor means being locked in anchoring position by said disc.

4. An engine starter according to claim 3 in which said means for connecting the control member and pinion includes a ring having slots therein, bonded to said spacing and power transmitting member, and said pinion having lugs engaged within said slots to form a detachable driving connection between the ring and pinion.

5. In an engine starter, a motor shaft, a pinion journalled on said motor shaft for movement into engagement with a member of an engine to be started and having a flange thereon, a screw shaft mounted on the power shaft having a shoulder formed by an enlargement thereof, means for securing the screw shaft on the power shaft including an anchor pin traversing said enlargement, means to actuate the pinion including a flange control member cooperating with said screw shaft, an enclosure sleeve of elastic material for positioning said pinion and transmitting torque thereto from the control member, ring members attached to the ends of said elastic sleeve, detachable coupling means between the control member and pinion member including lugs on said pinion and control members interfitting with slots in said ring members, and means for opposing drifting of the pinion from idle position, including a spring and a thimble for seating the spring, said thimble located against said shoulder and overlying the ends of the anchor pin.

DONALD L. MILLER.

REFERENCES orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,551,787 Bendix Sept. 1, 1925 1,862,806 Ringwald June 14, 1932 2,325,007 Douglas July 20, 1943 2,332,055 Buxton Oct. 19, 1943 2,098,866 Fitzgerald Nov. 9, 1937 2,370,649 Fitzgerald Mar. 6, 1945 

